Tris­[2‐(2‐oxazolin‐2‐yl)­phenolato]­iron(III)

The title compound, tris­[2‐(4,5‐dihydrooxazol‐2‐yl‐κN)phenolato‐κO]­iron(III), [Fe(C₉H₈NO₂)₃], is disordered over a non‐crystallographic twofold rotation axis perpendicular to the crystallographic threefold rotation axis. The disorder can be a pure rotational disorder of an iron complex in the facial configuration, or the consequence of a mixture of facial and meridional configurations. In the latter case, at least 25% of the iron complexes must adopt the facial configuration in order to obtain the disorder ratio observed in the crystal.     

High-resolution segmented EPI in a motor task fMRI study

A high-resolution gradient echo, multi-slice segmented echo planar imaging method was used for functional MRI (fMRI) using a motor task at 1.5 Tesla. Functional images with an in-plane resolution of 1 mm and slice thickness of 4 mm were obtained with good white-gray matter contrast. The multi-shot approach, combined with a short total readout period of 82 ms, limits blurring effects for short T(2)(*) tissues (such as gray matter), assuring truly high-resolution images. In all subjects, motor functions were clearly depicted in the contralateral central sulcus over several slices and sometimes activation was detected in the supplementary motor area and/or ipsilateral central sulcus. The average signal change of 11+/-3% was much higher than in standard low-resolution fMRI EPI experiments, as a result of larger relative blood fractions.     

T2* measurements in human brain at 1.5, 3 and 7 T

Measurements have been carried out in six subjects at magnetic fields of 1.5, 3 and 7 T, with the aim of characterizing the variation of T2* with field strength in human brain. Accurate measurement of T2* in the presence of macroscopic magnetic field inhomogeneity is problematic due to signal decay resulting from through-slice dephasing. The approach employed here allowed the signal decay due to through-slice dephasing to be characterized and removed from data, thus facilitating an accurate measurement of T2* even at ultrahigh field. Using double inversion recovery turbo spin-echo images for tissue classification, an analysis of T2* relaxation times in cortical grey matter and white matter was carried out, along with an evaluation of the variation of T2* with field strength in the caudate nucleus and putamen. The results show an approximately linear increase in relaxation rate R2* with field strength for all tissues, leading to a greater range of relaxation times across tissue types at 7 T that can be exploited in high-resolution T2*-weighted imaging.